1. Field of the Invention
The present invention relates to an organopolysiloxane composition for viscous fluid coupling. More specifically, the present invention relates to an organopolysiloxane viscous fluid coupler which undergoes little upward or downward variation in viscosity at elevated temperatures under higher shear and which is therefore stable for long periods of time.
2. Background Information
The proper viscosity, a high flash point, oxidation stability, stability against thermal decomposition, and a low temperature dependence on the part of the viscosity are required of fluids used as viscous coupler fluids. Therefore, fluid dimethylpolysiloxanes have generally been used heretofore.
However, fluid polydimethylsiloxanes alone may suffer from deterioration, such as an increase in viscosity or gelation, etc., after a certain period of time due to the heat generated by the violent shear forces and the friction in a fluid coupler. As a result, they lose their ability to function as coupler fluids.
Due to this, various improvements have been implemented in order to increase their shear stability and heat resistance. For example, functional fluids which are relatively stable with respect to viscosity increases and gelation at elevated temperatures under high shearing forces are disclosed in U.S. Pat. No. 2,445,567, issued July 20, 1948, to Elliott which describes an organopolysiloxane fluid which contains the iron salt of an organic acid; U.S. Pat. No. 3,328,350, which describes an amine compound-containing organopolysiloxane fluid; and Japanese Patent Publication No. 55-18457 [80-18457], published May 19, 1980, Toray Silicone Co., Ltd. which describes an organopolysiloxane fluid which contains an N-phenylaminophenyl group-containing polysiloxane.